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We investigated the prognostic significance of Death-Associated Protein Kinase 1 (DAPK1) and its role in sunitinib resistance in clear cell renal cell carcinoma (ccRCC). DAPK1 mRNA levels were significantly lower in tumor tissues than normal kidney tissues in TCGA-KIRC dataset (n=428). Both overall survival and disease-free survival were significantly shorter in ccRCC patients with low DAPK1 expression than those with high DAPK1 expression. Receiver operating characteristic curve analysis showed that low DAPK1 expression correlated with poor prognosis in ccRCC patients. Multivariate analysis confirmed that DAPK1 expression was an independent prognostic indicator in ccRCC. Gene set enrichment analysis showed that low DAPK1 expression correlates with upregulation of pathways related to metastasis, drug resistance, hypoxia and invasiveness in ccRCC patients. Sunitinib-resistant ccRCC cells show significantly lower DAPK1 mRNA and protein levels than sunitinib-sensitive ccRCC cells. DAPK1 overexpression enhances apoptosis in sunitinib-resistant ccRCC cells via the ATF6-dependent ER stress pathway. Xenograft tumors derived from DAPK1-overxpressing ccRCC cells were significantly smaller than the controls in nude mice. Our finding demonstrates that low DAPK1 expression is an independent prognostic indicator that correlates with ccRCC progression and sunitinib resistance.

Studies have demonstrated that oxidaive stress-induced apoptosis may be the main pathogenic mechanism of renal ischemia/reperfusion (I/R) injury. Theaflavin, a polyphenolic compound extracted from black tea, has been proven to exert strong antioxidant biological function. The objective of the present study was to investigate the potential role of theaflavin on renal I/R injury and its potential molecular mechanism both in vitro and in vivo. C57/BL6 J mice were used to create a model of I/R injury wherein mice were ligated with bilateral renal pedicles for 45 min, and then reperfused for 24 h. A hypoxia/reoxygenation (H/R) model of TCMK-1 cells was used to simulate I/R in vitro. Theaflavin were administered to the treatment group first and then established the model. Kidney Injury Molecule-1 (KIM-1), serum creatinine, urea nitrogen, and 24-h urinary protein levels were evaluated and changes in mitochondrial membrane potential and the ultrastructure of mitochondria were observed. Cell viability, oxidative stress damage, and apoptosis were assessed. The expression levels of nuclear factor erythroid 2-related factor 2 (Nrf2) and its downstream target genes HO-1 and NQO1 were evaluated. Our results revealed that pretreatment with theaflavin significantly inhibited I/R- and H/R-induced renal injury and cell apoptosis. Theaflavin improved mitochondrial dysfunction by attenuating mitochondrial damage and promoting mitochondrial membrane potential. Theaflavin pretreatment significantly reduced malondialdehyde content, while enhancing superoxide dismutase activity in vivo and in vitro. It also reduced oxidative stress and apoptosis mainly by upregulating Nrf2 and its downstream targets in TCMK-1 cells. Thus, theaflavin exerted a protective effect against renal I/R injury by inhibiting oxidative stress and apoptosis via activation of the Nrf2-NQO1/HO-1 pathway as well as correcting mitochondrial dysfunction, thereby presenting its potential as a clinical therapeutic in cases of acute kidney injury.

The primary purpose of the current study was to investigate the antitumor activity of limonene which is a plant monoterpene along with evaluating its effects on cell apoptosis, cell cycle phase distribution, cell migration and invasion.The cell proliferation of T24 bladder cancer cells was examined by WTS-1 assay. The apoptotic effects induced by limonene were investigated by a combination of fluorescence microscopy and flow cytometry and then confirmed by western blot assay. The effects of limonene on cell cycle in T24 bladder cancer cells were studied by flow cytometry. The effects on cell migration and invasion were examined by wound healing assay and transwell assay using Matrigel.The results showed that limonene induced cytotoxic effects and reduced cell viability of T24 human bladder cancer cells showing an IC50 value of 9 μM. Limonene also induced significant apoptosis in bladder cancer cells since it induced significant nuclear fragmentation, chromatin condensation, and splitting of the nucleus, representative of the apoptotic cascade. The apoptotic cell percentage was 1.95, 5.35, 15.61 and 34.71% at limonene concentrations of 0, 9, 18 and 36 µM. Further, the apoptotic effects of limonene were also confirmed by Western blot analysis and the results showed increase in the expression of Bax and caspase-3 and decrease of Bcl-2 expression. Limonene also caused G2/M phase cell cycle arrest as well as suppression of cell migration and invasion.These results indicate that limonene might be used as a potent anticancer agent against human bladder cancer for which further in depth studies are needed, especially over its toxicological studies.

Background Huachansu (HCS), a class of toxic steroids extracted from toad venom, which has been shown to be a valuable anticancer drug in many kinds of cancers. However, the effect of HCS on bladder cancer has not been elucidated. In this study, we focused on the antitumor activities and related mechanisms of HCS on bladder cancer in vitro and in vivo. Methods Cell viability of T24, EJ, RT-4, SV-HUC-1 cells after HCS treatment was measured by MTS, whereas the changes of cell morphology were observed by transmission electron microscopy. The early apoptosis induced by HCS was evaluated by flow cytometry, and the expression level of apoptosis-related molecules (Bax, Bcl-2, XIAP, PARP, cleaved-Caspases 3, 8, 9) was detected using Western blot. We then evaluated the impact of HCS on the expression of Fas/Fasl, TNF- alpha/TNFR1, and the activation of NF-Kappa B pathway, and furthermore the effect of these pathways in HCS induced-apoptosis were also detected. At last, xenograft tumor in nude mice was used to further investigate the antitumor effect of HCS in vivo. Results Our results showed that HCS could efficiently inhibit proliferation and induce apoptosis in human bladder cancer cell lines. The expression of Fas, Fasl, TNF- alpha were all elevated at both mRNA and protein level after HCS treatment. Furthermore, down regulation of TNF- alpha, TNFR1, Fas or inhibition of Fas/Fasl interaction decreased the relative number of death cells induced by HCS. In vivo, HCS treatment significantly suppressed tumor growth and induced apoptosis in xenografts tumor in nude mice. Conclusions HCS could efficiently inhibit proliferation and induce apoptosis in human bladder cancer cells in vitro and in vivo, which is largely mediated by Fas/Fasl and TNF- alpha/TNFR1 pathway. Electronic supplementary material The online version of this article (doi:10.1186/s13046-015-0134-9) contains supplementary material, which is available to authorized users.

Background Recently, leucine-rich repeats and immunoglobulin-like domains 1 (LRIG1), a negative regulator of EGFR, was discovered is a novel agent for suppressing bladder cancer. The aim of this study was to investigate the impact of LRIG1 on the biological features of aggressive bladder cancer cells and the possible mechanisms of enhanced apoptosis induced by upregulation of LRIG1. Methods In this study, we examined the mRNA and protein expression of LRIG1 and EGFR in bladder cancers and normal bladder. Meanwhile, we overexpressed LRIG1 with adenovirus vector in T24/5637 bladder cancer cell lines, and we used real time-PCR, western blot, and co-immunoprecipitation analysis in order to examine the effects of LRIG1 gene on EGFR. Furthermore, we evaluate the impact of LRIG1 gene on the function of human bladder cancer cells and EGFR signaling. Results The expression of LRIG1 was decreased, while the expression of EGFR was increased in the majority of bladder cancer, and the ratio of EGFR/LRIG1 was increased in tumors versus normal tissue. We found that upregulation of LRIG1 induced cell apoptosis and cell growth inhibition, and further reversed invasion in bladder cancer cell lines in vitro by inhibiting phosphorylation of downstream MAPK and AKT signaling pathway. Conclusion Taken together, our findings provide us with an insight into LRIG1 function, and we conclude that LRIG1 evolved in bladder cancer as a rare feedback negative attenuator of EGFR, thus could offer a novel therapeutic target to treat patients with bladder cancer.